dinosaur genera Diceratops Lull, 1905 and Microceratops Bohlin, 1953 are preoccupied by the Hymenoptera insects, Diceratops Foerster, 1868 and Microceratops Seyrig, 1952, respectively. Therefore, the name of the ceratopsian dinosaur Diceratops Lull, 1905 from the Late Cretaceous of United States is a junior homonym of the hymenoptera Diceratops Foerster, 1868. Diceratus n. gen. (Greek di ‘‘two,’’ Greek ceratos ‘‘horned’’) is proposed as the replacement name of Diceratops Lull, 1905. Some workers have considered Diceratops synonymous with Triceratops (e.g., Dodson and Currie, 1990) but it was reinstated by Forster (1996) after analysis of the characteristics of all existing ceratopsid skulls, and recent reviews (e.g., Dodson et al., 2004) have considered Diceratops a valid genus.
Due to preoccupation, the name of the ceratopsian dinosaur Microceratops Bohlin, 1953 from the Cretaceous of the Gobi is
a junior homonym of the insect Microceratops Seyrig, 1952. Microceratus n. gen. (Greek micro ‘‘small,’’ Greek ceratos ‘‘horned’’) is proposed as the replacing name of Microceratops Bohlin, 1953.
Sereno (2000:489) has declared Microceratops a nomen dubium since the holotype material lacks any diagnostic features, a
convention followed by You and Dodson (2004:480). However, the name is still used by Le Loeuff et al. (2002), Lucas (2006),
Alifanov (2003) and Xu et al. (2002), and such practice justiﬁes the renaming of the genus.
In order to preserve some stability, the names chosen here deliberately preserve the same preﬁxes.

The record of ornithischian dinosaurs from Portugal is substantial but incomplete in terms of our understanding of taxonomic composition and details of the anatomy of many forms. New data and reinterpretation of these forms are provided. The basal thyreophoran from the Lower Jurassic (the nomen dubium “Lusitanosaurus liasicus”) is the most primitive dinosaur from Iberia. Concerning the Late Jurassic, new material from the Lourinhã Formation (Kimmeridgian/Tithonian) referable to the stegosaur Dacentrurus provides additional information on the systematic position and osteology.
The new material shows two rows of paired triangular plates, with a notch in the anterior rim. A maxillary of an ankylosaur from the Vale Frades (Lourinhã Fm.) is here reported, but cannot be referable to Dracopelta, the only ankylosaur genus currently known from Portugal. The ornithopod Alocodon kuehnei reported as Middle Jurassic (Callovian) is probably Oxfordian in age. A right dentary (ML768 from Zimbral) from the Lourinhã Formation, Kimmeridgian/Tithonian, and shares affinities with Dryosaurus but possesses more denticulation and no secondary ridges, suggesting the occurrence of a new or unreported species for the Late Jurassic of Portugal, which is here tentatively ascribed to aff. Dryosaurus sp. In summary, the Late Jurassic ornithischians species/genera from Portugal include Dacentrurus armatus, Stegosaurus cf. ungulatus, Dracopelta zbyszewskii, Phyllodon henkeli, Hypsilophodon sp., Alocodon kuehnei, Trimucrodon cuneatus, aff. Dryosaurus and Draconyx loureiroi. The Lower Cretaceous (Hauterivian / Barremian) of Praia das Aguncheiras, in Cabo Espichel, provided a partial left maxillary (CPGP.1.99.7) of a basal iguanodontian that shows affinities with Camptosaurus, and is tentatively assigned to this genus. The maxillary teeth denticles differ from Iguanodon or other Iguanodontoidea because not show mammillations. More material is necessary to validate but, to be true, that would confirm the presence of this genus in the lower Cretaceous. The Iguanodon has been well reported in the Lower Cretaceous of Cabo Espichel.

The Late Jurassic Lourinhã Formation contains a diverse dinosaur fauna comprising theropods, sauropods, stegosaurs, ankylosaurs and several genera of ornithopods.
The sedimentology in the area favours preservation of footprints, and footprints from most of the dinosaurs represented by skeletal remains are present in the area. During fieldwork in the summer of 2003 a new, large, tridactyl footprint was found at the beach of Vale Frades, approximately 6 km north of Lourinhã, Portugal. The footprint was found together with a stegosaur footprint on a clay bed exposed within the tidal zone. The footprints were preserved as sandstone casts standing on a pedestal of clay. This unusual type of preservation is the result of the footprints having first been emplaced in clay, and then filled with sand. During the present day erosion from the sea, the harder sandstone cast of the footprints protects the subjacent clay layers from erosion. Owing to the immediate danger of erosion of, the footprint was collected and is now on display at Museu da Lourinhã (ML 1000). The footprint is 70 cm long and 69 cm wide, the toes are short and broad, with indications of short blunt claws. The

divarication angle between the outer digits is close to 90 degrees. The dimensions and general

morphology of the footprint identifies it as deriving from an ornithopod dinosaur with an estimated hip height of 4.13 metres. Although very large ornithopods are known from the Cretaceous, the largest known Jurassic ornithopod is Camptosaurus from USA, and the largest known from Portugal is the camptosaurid Draconyx loureiroi. Neither of these reached the body size suggested by the new footprint. So far the footprint described herein is s the only evidence for a Jurassic ornithopod of that size.